reactivity.html - n.
1 the act or an instance of reacting; a responsive or reciprocal action.
2 a a responsive feeling (what was your reaction to the news?). b an immediate or first impression.
3 the occurrence of a (physical or emotional) condition after a period of its opposite.
4 a bodily response to an external stimulus, e.g. a drug.
5 a tendency to oppose change or to advocate return to a former system, esp. in politics.
6 the interaction of substances undergoing chemical change.
7 propulsion by emitting a jet of particles etc. in the direction opposite to that of the intended motion.

reactionist n. & adj. [REACT + -ION or med.L reactio (as RE-, ACTION)]

reactivity.html - adj. & n.
--adj.

tending to oppose (esp. political) change and advocate return to a former system.

--n.

(pl. -ies) a reactionary person.

reactivity.html - v.tr.
restore to a state of activity; bring into action again.

reactivation n.

reactivity.html - adj.
1 showing reaction.
2 of or relating to reactance.

reactivity n.

reactivity.html - v.
1 intr. (foll. by to) respond to a stimulus; undergo a change or show behaviour due to some influence (how did they react to the news?).
2 intr. (often foll. by against) be actuated by repulsion to; tend in a reverse or contrary direction.
3 intr. (often foll. by upon) produce a reciprocal or responsive effect; act upon the agent (they react upon each other).
4 intr. (foll. by with) Chem. & Physics (of a substance or particle) be the cause of activity or interaction with another (nitrous oxide reacts with the metal).
5 tr. (foll. by with) Chem. cause (a substance) to react with another.
6 intr. Mil. make a counter-attack.
7 intr. Stock Exch. (of shares) fall after rising. [RE- + ACT or med.L reagere react- (as RE-, L agere do, act)]

reactivity.html - n.
Electr. a component of impedance in an AC circuit, due to capacitance or inductance or both.